diff options
Diffstat (limited to 'drivers/staging/zram/zram_drv.c')
| -rw-r--r-- | drivers/staging/zram/zram_drv.c | 857 |
1 files changed, 857 insertions, 0 deletions
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c new file mode 100644 index 00000000..2ba506ab --- /dev/null +++ b/drivers/staging/zram/zram_drv.c @@ -0,0 +1,857 @@ +/* + * Compressed RAM block device + * + * Copyright (C) 2008, 2009, 2010 Nitin Gupta + * + * This code is released using a dual license strategy: BSD/GPL + * You can choose the licence that better fits your requirements. + * + * Released under the terms of 3-clause BSD License + * Released under the terms of GNU General Public License Version 2.0 + * + * Project home: http://compcache.googlecode.com + */ + +#define KMSG_COMPONENT "zram" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#ifdef CONFIG_ZRAM_DEBUG +#define DEBUG +#endif + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/bio.h> +#include <linux/bitops.h> +#include <linux/blkdev.h> +#include <linux/buffer_head.h> +#include <linux/device.h> +#include <linux/genhd.h> +#include <linux/highmem.h> +#include <linux/slab.h> +#include <linux/lzo.h> +#include <linux/string.h> +#include <linux/vmalloc.h> + +#include "zram_drv.h" + +#define LZO_ALGO_SW 0 +#define LZO_ALGO_HW 1 + +#ifdef CONFIG_LZO_HW_ALGO +#define zram_compress lzo1x_1_compress_hw +#define zram_decompress_safe lzo1x_decompress_safe_hw +static uint lzo_algo_type = LZO_ALGO_HW; +bool lzo_sw_flag; +#else +#define zram_compress lzo1x_1_compress +#define zram_decompress_safe lzo1x_decompress_safe +static uint lzo_algo_type = LZO_ALGO_SW; +#endif + +module_param_named(lzo_algo_type, lzo_algo_type, uint, S_IRUGO); + +/* Globals */ +static int zram_major; +struct zram *zram_devices; + +/* Module params (documentation at end) */ +static unsigned int num_devices = 1; + +static void zram_stat64_add(struct zram *zram, u64 *v, u64 inc) +{ + spin_lock(&zram->stat64_lock); + *v = *v + inc; + spin_unlock(&zram->stat64_lock); +} + +static void zram_stat64_sub(struct zram *zram, u64 *v, u64 dec) +{ + spin_lock(&zram->stat64_lock); + *v = *v - dec; + spin_unlock(&zram->stat64_lock); +} + +static void zram_stat64_inc(struct zram *zram, u64 *v) +{ + zram_stat64_add(zram, v, 1); +} + +static int zram_test_flag(struct zram_meta *meta, u32 index, + enum zram_pageflags flag) +{ + return meta->table[index].flags & BIT(flag); +} + +static void zram_set_flag(struct zram_meta *meta, u32 index, + enum zram_pageflags flag) +{ + meta->table[index].flags |= BIT(flag); +} + +static void zram_clear_flag(struct zram_meta *meta, u32 index, + enum zram_pageflags flag) +{ + meta->table[index].flags &= ~BIT(flag); +} + +static int page_zero_filled(void *ptr) +{ + unsigned int pos; + unsigned long *page; + + page = (unsigned long *)ptr; + + for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) { + if (page[pos]) + return 0; + } + + return 1; +} + +static void zram_free_page(struct zram *zram, size_t index) +{ + struct zram_meta *meta = zram->meta; + unsigned long handle = meta->table[index].handle; + u16 size = meta->table[index].size; + + if (unlikely(!handle)) { + /* + * No memory is allocated for zero filled pages. + * Simply clear zero page flag. + */ + if (zram_test_flag(meta, index, ZRAM_ZERO)) { + zram_clear_flag(meta, index, ZRAM_ZERO); + zram->stats.pages_zero--; + } + return; + } + + if (unlikely(size > max_zpage_size)) + zram->stats.bad_compress--; + + zs_free(meta->mem_pool, handle); + + if (size <= PAGE_SIZE / 2) + zram->stats.good_compress--; + + zram_stat64_sub(zram, &zram->stats.compr_size, + meta->table[index].size); + zram->stats.pages_stored--; + + meta->table[index].handle = 0; + meta->table[index].size = 0; +} + +static void handle_zero_page(struct bio_vec *bvec) +{ + struct page *page = bvec->bv_page; + void *user_mem; + + user_mem = kmap_atomic(page); + memset(user_mem + bvec->bv_offset, 0, bvec->bv_len); + kunmap_atomic(user_mem); + + flush_dcache_page(page); +} + +static inline int is_partial_io(struct bio_vec *bvec) +{ + return bvec->bv_len != PAGE_SIZE; +} + +static int zram_decompress_page(struct zram *zram, char *mem, u32 index) +{ + int ret = LZO_E_OK; + size_t clen = PAGE_SIZE; + unsigned char *cmem; + struct zram_meta *meta = zram->meta; + unsigned long handle = meta->table[index].handle; + + if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) { + memset(mem, 0, PAGE_SIZE); + return 0; + } + + cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO); + if (meta->table[index].size == PAGE_SIZE) + memcpy(mem, cmem, PAGE_SIZE); + else + ret = zram_decompress_safe(cmem, meta->table[index].size, + mem, &clen); + zs_unmap_object(meta->mem_pool, handle); + + /* Should NEVER happen. Return bio error if it does. */ + if (unlikely(ret != LZO_E_OK)) { + pr_err("Decompression failed! err=%d, page=%u\n", ret, index); + zram_stat64_inc(zram, &zram->stats.failed_reads); + return ret; + } + + return 0; +} + +static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, + u32 index, int offset, struct bio *bio) +{ + int ret; + struct page *page; + unsigned char *user_mem, *uncmem = NULL; + struct zram_meta *meta = zram->meta; + page = bvec->bv_page; + + if (unlikely(!meta->table[index].handle) || + zram_test_flag(meta, index, ZRAM_ZERO)) { + handle_zero_page(bvec); + return 0; + } + + if (is_partial_io(bvec)) + /* Use a temporary buffer to decompress the page */ + uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); + + user_mem = kmap_atomic(page); + if (!is_partial_io(bvec)) + uncmem = user_mem; + + if (!uncmem) { + pr_info("Unable to allocate temp memory\n"); + ret = -ENOMEM; + goto out_cleanup; + } + + ret = zram_decompress_page(zram, uncmem, index); + /* Should NEVER happen. Return bio error if it does. */ + if (unlikely(ret != LZO_E_OK)) + goto out_cleanup; + + if (is_partial_io(bvec)) + memcpy(user_mem + bvec->bv_offset, uncmem + offset, + bvec->bv_len); + + flush_dcache_page(page); + ret = 0; +out_cleanup: + kunmap_atomic(user_mem); + if (is_partial_io(bvec)) + kfree(uncmem); + return ret; +} + +static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, + int offset) +{ + int ret = 0; + size_t clen; + unsigned long handle; + struct page *page; + unsigned char *user_mem, *cmem, *src, *uncmem = NULL; + struct zram_meta *meta = zram->meta; + + page = bvec->bv_page; + src = meta->compress_buffer; + + if (is_partial_io(bvec)) { + /* + * This is a partial IO. We need to read the full page + * before to write the changes. + */ + uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); + if (!uncmem) { + ret = -ENOMEM; + goto out; + } + ret = zram_decompress_page(zram, uncmem, index); + if (ret) + goto out; + } + + /* + * System overwrites unused sectors. Free memory associated + * with this sector now. + */ + if (meta->table[index].handle || + zram_test_flag(meta, index, ZRAM_ZERO)) + zram_free_page(zram, index); + + user_mem = kmap_atomic(page); + + if (is_partial_io(bvec)) { + memcpy(uncmem + offset, user_mem + bvec->bv_offset, + bvec->bv_len); + kunmap_atomic(user_mem); + user_mem = NULL; + } else { + uncmem = user_mem; + } + + if (page_zero_filled(uncmem)) { + kunmap_atomic(user_mem); + zram->stats.pages_zero++; + zram_set_flag(meta, index, ZRAM_ZERO); + ret = 0; + goto out; + } + + ret = zram_compress(uncmem, PAGE_SIZE, src, &clen, + meta->compress_workmem); + + if (!is_partial_io(bvec)) { + kunmap_atomic(user_mem); + user_mem = NULL; + uncmem = NULL; + } + + if (unlikely(ret != LZO_E_OK)) { +#ifdef CONFIG_LZO_HW_ALGO + if(ret == LZO_HW_OUT_LEN_ERROR) + { + clen = PAGE_SIZE; + ret = LZO_E_OK; + } + else +#endif + { + pr_err("Compression failed! err=%d\n", ret); + goto out; + } + } + + if (unlikely(clen > max_zpage_size)) { + zram->stats.bad_compress++; + clen = PAGE_SIZE; + src = NULL; + if (is_partial_io(bvec)) + src = uncmem; + } + + handle = zs_malloc(meta->mem_pool, clen); + if (!handle) { + pr_info("Error allocating memory for compressed " + "page: %u, size=%zu\n", index, clen); + ret = -ENOMEM; + goto out; + } + cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO); + + if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) + src = kmap_atomic(page); + memcpy(cmem, src, clen); + if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) + kunmap_atomic(src); + + zs_unmap_object(meta->mem_pool, handle); + + meta->table[index].handle = handle; + meta->table[index].size = clen; + + /* Update stats */ + zram_stat64_add(zram, &zram->stats.compr_size, clen); + zram->stats.pages_stored++; + if (clen <= PAGE_SIZE / 2) + zram->stats.good_compress++; + +out: + if (is_partial_io(bvec)) + kfree(uncmem); + + if (ret) + zram_stat64_inc(zram, &zram->stats.failed_writes); + return ret; +} + +static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, + int offset, struct bio *bio, int rw) +{ + int ret; + + if (rw == READ) { + down_read(&zram->lock); + ret = zram_bvec_read(zram, bvec, index, offset, bio); + up_read(&zram->lock); + } else { + down_write(&zram->lock); + ret = zram_bvec_write(zram, bvec, index, offset); + up_write(&zram->lock); + } + + return ret; +} + +static void update_position(u32 *index, int *offset, struct bio_vec *bvec) +{ + if (*offset + bvec->bv_len >= PAGE_SIZE) + (*index)++; + *offset = (*offset + bvec->bv_len) % PAGE_SIZE; +} + +static void __zram_make_request(struct zram *zram, struct bio *bio, int rw) +{ + int i, offset; + u32 index; + struct bio_vec *bvec; + + switch (rw) { + case READ: + zram_stat64_inc(zram, &zram->stats.num_reads); + break; + case WRITE: + zram_stat64_inc(zram, &zram->stats.num_writes); + break; + } + + index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT; + offset = (bio->bi_sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT; + + bio_for_each_segment(bvec, bio, i) { + int max_transfer_size = PAGE_SIZE - offset; + + if (bvec->bv_len > max_transfer_size) { + /* + * zram_bvec_rw() can only make operation on a single + * zram page. Split the bio vector. + */ + struct bio_vec bv; + + bv.bv_page = bvec->bv_page; + bv.bv_len = max_transfer_size; + bv.bv_offset = bvec->bv_offset; + + if (zram_bvec_rw(zram, &bv, index, offset, bio, rw) < 0) + goto out; + + bv.bv_len = bvec->bv_len - max_transfer_size; + bv.bv_offset += max_transfer_size; + if (zram_bvec_rw(zram, &bv, index+1, 0, bio, rw) < 0) + goto out; + } else + if (zram_bvec_rw(zram, bvec, index, offset, bio, rw) + < 0) + goto out; + + update_position(&index, &offset, bvec); + } + + set_bit(BIO_UPTODATE, &bio->bi_flags); + bio_endio(bio, 0); + return; + +out: + bio_io_error(bio); +} + +/* + * Check if request is within bounds and aligned on zram logical blocks. + */ +static inline int valid_io_request(struct zram *zram, struct bio *bio) +{ + u64 start, end, bound; + + /* unaligned request */ + if (unlikely(bio->bi_sector & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1))) + return 0; + if (unlikely(bio->bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1))) + return 0; + + start = bio->bi_sector; + end = start + (bio->bi_size >> SECTOR_SHIFT); + bound = zram->disksize >> SECTOR_SHIFT; + /* out of range range */ + if (unlikely(start >= bound || end > bound || start > end)) + return 0; + + /* I/O request is valid */ + return 1; +} + +/* + * Handler function for all zram I/O requests. + */ +static void zram_make_request(struct request_queue *queue, struct bio *bio) +{ + struct zram *zram = queue->queuedata; + + down_read(&zram->init_lock); + if (unlikely(!zram->init_done)) + goto error; + + if (!valid_io_request(zram, bio)) { + zram_stat64_inc(zram, &zram->stats.invalid_io); + goto error; + } + + __zram_make_request(zram, bio, bio_data_dir(bio)); + up_read(&zram->init_lock); + + return; + +error: + up_read(&zram->init_lock); + bio_io_error(bio); +} + +static void __zram_reset_device(struct zram *zram) +{ + size_t index; + struct zram_meta *meta; + + if (!zram->init_done) + return; + + meta = zram->meta; + zram->init_done = 0; + + /* Free all pages that are still in this zram device */ + for (index = 0; index < zram->disksize >> PAGE_SHIFT; index++) { + unsigned long handle = meta->table[index].handle; + if (!handle) + continue; + + zs_free(meta->mem_pool, handle); + } + + zram_meta_free(zram->meta); + zram->meta = NULL; + /* Reset stats */ + memset(&zram->stats, 0, sizeof(zram->stats)); + + zram->disksize = 0; + set_capacity(zram->disk, 0); +} + +void zram_reset_device(struct zram *zram) +{ + down_write(&zram->init_lock); + __zram_reset_device(zram); + up_write(&zram->init_lock); +} + +void zram_meta_free(struct zram_meta *meta) +{ + zs_destroy_pool(meta->mem_pool); + kfree(meta->compress_workmem); + free_pages((unsigned long)meta->compress_buffer, 1); + vfree(meta->table); + kfree(meta); +} + +struct zram_meta *zram_meta_alloc(u64 disksize) +{ + size_t num_pages; + struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL); + if (!meta) + goto out; + + meta->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL); + if (!meta->compress_workmem) + goto free_meta; + + meta->compress_buffer = + (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1); + if (!meta->compress_buffer) { + pr_err("Error allocating compressor buffer space\n"); + goto free_workmem; + } + + num_pages = disksize >> PAGE_SHIFT; + meta->table = vzalloc(num_pages * sizeof(*meta->table)); + if (!meta->table) { + pr_err("Error allocating zram address table\n"); + goto free_buffer; + } + + meta->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM); + if (!meta->mem_pool) { + pr_err("Error creating memory pool\n"); + goto free_table; + } + + return meta; + +free_table: + vfree(meta->table); +free_buffer: + free_pages((unsigned long)meta->compress_buffer, 1); +free_workmem: + kfree(meta->compress_workmem); +free_meta: + kfree(meta); + meta = NULL; +out: + return meta; +} + +void zram_init_device(struct zram *zram, struct zram_meta *meta) +{ + if (zram->disksize > 2 * (totalram_pages << PAGE_SHIFT)) { + pr_info( + "There is little point creating a zram of greater than " + "twice the size of memory since we expect a 2:1 compression " + "ratio. Note that zram uses about 0.1%% of the size of " + "the disk when not in use so a huge zram is " + "wasteful.\n" + "\tMemory Size: %lu kB\n" + "\tSize you selected: %llu kB\n" + "Continuing anyway ...\n", + (totalram_pages << PAGE_SHIFT) >> 10, zram->disksize >> 10 + ); + } + + /* zram devices sort of resembles non-rotational disks */ + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue); + + zram->meta = meta; + zram->init_done = 1; + + pr_debug("Initialization done!\n"); +} + +static void zram_slot_free_notify(struct block_device *bdev, + unsigned long index) +{ + struct zram *zram; + + zram = bdev->bd_disk->private_data; + zram_free_page(zram, index); + zram_stat64_inc(zram, &zram->stats.notify_free); +} + +static const struct block_device_operations zram_devops = { + .swap_slot_free_notify = zram_slot_free_notify, + .owner = THIS_MODULE +}; + +#ifdef CONFIG_E_SHOW_MEM + +static u64 zram_stat64_read(struct zram *zram, u64 *v) +{ + u64 val; + + spin_lock(&zram->stat64_lock); + val = *v; + spin_unlock(&zram->stat64_lock); + + return val; +} + +static int zram_e_show_mem_handler(struct notifier_block *nb, + unsigned long val, void *data) +{ + int i; + u64 size = 0; + struct zram *zram = NULL; + struct zram_meta *meta; + unsigned long *used = data; + unsigned long total_used = 0; + enum e_show_mem_type type = val; + + printk("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n"); + printk("Enhanced Mem-info :ZRAM\n"); + + for (i = 0; i < zram_get_num_devices(); i++) { + zram = &zram_devices[i]; + meta = zram->meta; + down_read(&zram->init_lock); + if (zram->init_done) { + size = zs_get_total_size_bytes(meta->mem_pool); + *used += ((unsigned long)size) >> PAGE_SHIFT; + total_used += ((unsigned long)size) >> PAGE_SHIFT; + } + up_read(&zram->init_lock); + } + + printk("Detail:\n"); + for (i = 0; i < zram_get_num_devices(); i++) { + zram = &zram_devices[i]; + meta = zram->meta; + if (E_SHOW_MEM_CLASSIC == type || E_SHOW_MEM_ALL == type) { + printk(" orig:%lu pages, %lu kB\n", + (unsigned long) zram->stats.pages_stored, + (unsigned long)((zram->stats.pages_stored) + << PAGE_SHIFT) / 1024); + printk(" compressed:%lu kB\n", + (unsigned long)zram_stat64_read(zram, + &zram->stats.compr_size) / 1024); + } + + if (E_SHOW_MEM_ALL == type) { + /* todo: */ + } + } + + printk("Total used:%lu pages, %lu kB\n", total_used, + (total_used << PAGE_SHIFT) / 1024); + return 0; +} + +static struct notifier_block zram_e_show_mem_notifier = { + .notifier_call = zram_e_show_mem_handler, +}; +#endif + +static int create_device(struct zram *zram, int device_id) +{ + int ret = -ENOMEM; + + init_rwsem(&zram->lock); + init_rwsem(&zram->init_lock); + spin_lock_init(&zram->stat64_lock); + + zram->queue = blk_alloc_queue(GFP_KERNEL); + if (!zram->queue) { + pr_err("Error allocating disk queue for device %d\n", + device_id); + goto out; + } + + blk_queue_make_request(zram->queue, zram_make_request); + zram->queue->queuedata = zram; + + /* gendisk structure */ + zram->disk = alloc_disk(1); + if (!zram->disk) { + pr_warn("Error allocating disk structure for device %d\n", + device_id); + goto out_free_queue; + } + + zram->disk->major = zram_major; + zram->disk->first_minor = device_id; + zram->disk->fops = &zram_devops; + zram->disk->queue = zram->queue; + zram->disk->private_data = zram; + snprintf(zram->disk->disk_name, 16, "zram%d", device_id); + + /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */ + set_capacity(zram->disk, 0); + + /* + * To ensure that we always get PAGE_SIZE aligned + * and n*PAGE_SIZED sized I/O requests. + */ + blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE); + blk_queue_logical_block_size(zram->disk->queue, + ZRAM_LOGICAL_BLOCK_SIZE); + blk_queue_io_min(zram->disk->queue, PAGE_SIZE); + blk_queue_io_opt(zram->disk->queue, PAGE_SIZE); + + add_disk(zram->disk); + + ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj, + &zram_disk_attr_group); + if (ret < 0) { + pr_warn("Error creating sysfs group"); + goto out_free_disk; + } + + zram->init_done = 0; + return 0; + +out_free_disk: + del_gendisk(zram->disk); + put_disk(zram->disk); +out_free_queue: + blk_cleanup_queue(zram->queue); +out: + return ret; +} + +static void destroy_device(struct zram *zram) +{ + sysfs_remove_group(&disk_to_dev(zram->disk)->kobj, + &zram_disk_attr_group); + + if (zram->disk) { + del_gendisk(zram->disk); + put_disk(zram->disk); + } + + if (zram->queue) + blk_cleanup_queue(zram->queue); +} + +unsigned int zram_get_num_devices(void) +{ + return num_devices; +} + +static int __init zram_init(void) +{ + int ret, dev_id; + + if (num_devices > max_num_devices) { + pr_warn("Invalid value for num_devices: %u\n", + num_devices); + ret = -EINVAL; + goto out; + } + + zram_major = register_blkdev(0, "zram"); + if (zram_major <= 0) { + pr_warn("Unable to get major number\n"); + ret = -EBUSY; + goto out; + } + + /* Allocate the device array and initialize each one */ + zram_devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL); + if (!zram_devices) { + ret = -ENOMEM; + goto unregister; + } + + for (dev_id = 0; dev_id < num_devices; dev_id++) { + ret = create_device(&zram_devices[dev_id], dev_id); + if (ret) + goto free_devices; + } + pr_info("Created %u device(s) ...\n", num_devices); + +#ifdef CONFIG_E_SHOW_MEM + register_e_show_mem_notifier(&zram_e_show_mem_notifier); +#endif + return 0; + +free_devices: + while (dev_id) + destroy_device(&zram_devices[--dev_id]); + kfree(zram_devices); +unregister: + unregister_blkdev(zram_major, "zram"); +out: + return ret; +} + +static void __exit zram_exit(void) +{ + int i; + struct zram *zram; + + for (i = 0; i < num_devices; i++) { + zram = &zram_devices[i]; + + get_disk(zram->disk); + destroy_device(zram); + zram_reset_device(zram); + put_disk(zram->disk); + } + + unregister_blkdev(zram_major, "zram"); + + kfree(zram_devices); +#ifdef CONFIG_E_SHOW_MEM + unregister_e_show_mem_notifier(&zram_e_show_mem_notifier); +#endif + pr_debug("Cleanup done!\n"); +} + +module_param(num_devices, uint, 0); +MODULE_PARM_DESC(num_devices, "Number of zram devices"); + +module_init(zram_init); +module_exit(zram_exit); + +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>"); +MODULE_DESCRIPTION("Compressed RAM Block Device"); |